Hydrogenation of lubricating oils



United States are This invention relates to the hydrogenation of lubricating oils, and it particularly concerns the use of an improved catarlyst for use therein.

An object of the present invention is to provide a method for improving the quality of lubricating oils. Another object is to provide a highly effective catalyst for the hydrogenation of lubricating oils. A further object is to provide a hydrogenation process for improving the quality of lubricating oils which employs a novel catalyst especially effective for improving the viscosity index of the lubricating oil.

It has been found that a fluoride promoted catalyst, which catalyst is comprised of minor amounts of the oxides and sulfides of cobalt and molybdenum and a major amount of an alumina carrier, is highly effective for the hydrogenation of a lubricating oil for improvement of its properties, especially for improving the viscosity index of the lubricating oil. Such a catalyst may contain between 1 and 10% of the oxides and sulfides of cobalt; between 2 and 20% of the oxides and sulfides of molybdenum; between 0.1 and 10% of fluoride added as an inorganic fluoride e.g. ammonium fluoride, hydrogen fluoride; and the remainder essentially alumina. The

amount of fluoride is preferably between 1 and 5% The addition of the fluoride to the catalyst enables the latter to produce a hydrogenated lubricating oil which has a higher viscosity index than if the catalyst had no added fluoride. In this sense it promotes the catalyst. Hydrogenation conditions comprise a temperature between 600 and 900 F., preferably between 750 and 850 F. and a pressure between 500 and 3000 psig.

The lubricating oils which may be processed in accordance with this invention comprise either the total raw lubricating oil as obtained from the high boiling fractions of crude oil, or it may be a refined lubricating oil such as one which has been solvent extracted and/ or dewaxed. It can consist of any of the individual lubricating oil fractions such as are segregated with respect to viscosity and boiling range, or it may consist of the total'lubricating oil obtained from crude oil prior to fractionating the lubricating oil into the individual SAE 5, 10, 2'0, 40, 50, etc. grades. The lubricating oils are normally virgin 3,105,813 Fatented Get. l, 1 963 of fluoride added as ammonium fluoride, hydrogen fluoride, or other inorganic fluoride.

The method of preparing the catalyst is not critical. A highly convenient Way is to first prepare an aluminasupported cobalt oxide-molybdenum oxide catalyst. Such compositions have been employed as catalysts in hydro desulfunizing petroleum oils. Many methods for preparing them have been detailed in the prior art. vCatalyst manufacturing techniques such as co-precipitation, cogelation, impregnation and the like may be used in their manufacture. For example, activated alumina pellets or granules may be impregnated with the proper amounts of aqueous solutions of Water soluable cobalt compounds such as cobalt nitrate and Water soluble molybdenum compounds, such as ammonium molybdate. The composition is then'dried and calcined at an elevated temperature, cg. 1000 -F., whereupon the cobalt and molybdenum compounds are decomposed to their oxides. A double impregnation technique is'taught in U.S. 2,687,- 381 to-G. W. Hendricks. A preferred method consists of preparing a molybdenum oxide-alumina catalyst (such as have been used for many years as hydroiorming catalysts land which may be prepared by precipitating aqueous solutions of soluble molybdenum and aluminum compounds, drying, and calcining) and impregnating the molybdenum oxide-alumina hydroforming catalyst with an aqueous solution of a soluble cobalt salt, drying and then calcining.

The fluoride may'be incorporated within the catalyst by any of a number of techniques. -The calcined cobalt oxide-molybdenum oxide-alumina may'be impregnated with a calculated volume of an. aqueous solution of ammonium fluoride, hydrogen fluoride, etc. of the desired alumina carrier.

concentration so that upon evaporation of the water,

the catalyst is impregnated with the desired amount of within the catalyst during the co-precipitation, -co-gelation or impregnation step during which step the cobalt =oxide-and molybdenum oxide are incorporated with the The inorganic fluoride can be added -in small amounts to the lubricating oil charged to the distillates having viscosities at 100 F. in the range from about 100 to l0O0'Saybolt seconds, with viscosity indexes in the range ofabout -50 to 1100. These generally boil above about 700 F. at 760 mm. Hg pressure.

The catalyst used in this invention is comprised of minor amounts of the oxides and sulfides of cobalt and molybdenum supported on a major proportion of an alumina carrier and promoted with minor amounts of a fluoride. It may contain between 1 and 10% of the oxides and sulfides of cobalt, between 2 and 20% of the oxides and sulfides of molybdenum, between 0.1 and 40% of an inorganic fluoride, and supported on an activated alumina (gamma alumina or forms thereof such as eta alumina, but not alpha alumina) carrier. Minor amounts of impurities may be contained in the catalyst of course, for example graphite may be present therein due to its use as a binder when preparing the catalyst in pelleted form. When the composition of the catalyst is described herein, use of the term percentage is to be understood to mean percent by weight. The fluoride and the amount thereof may suitably be from 1 to 5 hydrogenation reactor and thusdeposited within the catalyst. During its use in the hydrogenation process, the

cobalt and molybdenum oxides may become converted in part to their corresponding sulfides.

Hydrogenation of the lubricating oil is carried out a a temperature between about 600 and 900 F., preferably between about 750 and 850 F. Pressures between about 500 and 3000 p.s.i.g., for example between about 500 and 2000 p.s;i.g.', may be used. "It is not essential to use high purity hydrogen, and hydrogen streams such as are produced during naphtha reforming operations may suitably be employed. The hydrogen stream may be used in the amount of from 1000' to 5000'cuifitl'perbarrel of oil, e. g. 3000 cu. ft per ba'rrel'of oil.' Space velocities' of from 0.5 to 20, e.g. between 1 to 10, liquid volumes of oil/hour/volume of catalyst can be used.

During the hydrogenation step, substantial desulfurization and denitno-genation of the lubricating oil takes 0 oil at various temperatures. tained with respect to the viscosity index of the charge fride. This enables production of a higher viscosity index lubricating oil at a given hydrogenation temperature, or enables the use of lower temperatures during the hydrogenation step when great increases in viscosity index are not as essential.

Certain experiments were carried out which illustrate the advantages of the present invention. The lubricating oil employed as charge stock in these experiments consisted of a blend of different grades of a dewaxed chlorex extracted lubricating oil. The blend was composed of 30 volume percent of SAE E10 oil, 40 volume percent SAE 20 oil, and 30 volume percent SAE 40 oil. The viscosity indexes of the blend and the individual SAE 10, 20, and 40 fractions are given in the table which follows hereinafter. In the experiments, a stainless steel reactor containing 200 cc. of catalyst supported in its center section was employed. The reactor had a glassbead preheat zone above the catalyst. Lubricating oil and the hydrogen, as separate streams, were passed in a concurrent manner into the top of the reactor where they became heated in the preheat zone. The reactor was maintained under a pressure of 1000 p.s.i.g.; the oil being introduced at a space velocity of 2.5 liquid volumes/hour/volume of catalysts; and the hydrogen was employed at a rate approximating 3000 s.c.f./barrel of oil. The reactants passed downwardly through the catalyst bed and were removed from the bottom of the reactor. Gas was removed from the total effluent and the liquid product was topped to remove naphtha and light gas oil. The lubricating oil product was fractionated under 0.=1 to 0.2 mm. Hg abs. to provide 10 fractions. These fractions were analyzed for viscosity index and viscosity, and were thereafter combined in a manner so as to produce SAE 10, 20, and 40 fractions such as had been used in preparing the blend charged to the hydrogenation reaction. The SAE 10, 20, and 40 fractions were then compared with respect to viscosity index with the corresponding fractions that made up the charge lubricating oil.

The catalyst used in the experiments was a commercial catalyst containing 3.65 weight percent C00, 11.60 weight percent M and the remainder essentially activated alumina. When fluorided catalyst was used in the experiments, it was prepared by soaking the above defined catalyst in a solution of ammonium fluoride in distilled water so as to incorporate 1% fluoride in the catalyst. This solution was slowly evaporated almost to the point of dryness. The catalyst was dried in an oven and thereafter calcined at 1000 F. for 4 hours,

during which time ammonia was evolved. 7 Both the fiuorided catalyst and the non-fluorided catalyst were employed for the hydrogenation of the blended lubricating The results which were oband the product lubricating oil fractions are shown in the It should be noted from the above results that when the product, when using a fluorided catalyst in place of a non-fluorided catalyst.

While the invention has been described with reference to certain examples it should not be construed as limited thereto but includes within its scope such modifications as would ordinarily occur to those skilled in the art. 1

Thus having described the invention what is claimed is;

.1. A process for improving the viscosity index of lubricating oil having a viscosity index in the range of -50 to 100 with hydrogen at a temperature between about 600 and 900 F. and a pressure between about 500 and 3000 p.s.i.g. in the presence of a catalyst comprised of a minor amount of the oxides and sulfides of cobalt and molybdenum, 0.1 to 10% by weight of an inorganic fluoride, and an alumina carrier, and recovering a lubricating oil having an increased viscosity index.

2. The process of claim 1 in which the catalyst is comprised of between about 1 and'l0% by weight of the oxides and sulfides of cobalt, between about 2 and 20% by weight of the oxides and sulfides of molybdenum, be tween about 0.1 and 10% by weight of aninorganic fluoride and the remainder essentially alumina.

3. The process of claim 2 in which the fluoride is ammonium fluoride.

4. The process of claim 2 in which the fluoride is hydrogen fluoride.

SVA process for improving the viscosity index of lubricating oils which comprises contacting a lubricating oil having viscosity index in the-range of 50 to with hydrogen in the amountof about 1000 to 5000 cu. ft. of hydrogen per barrel of oilat a temperature between about 750 and 850 F. and a pressure between about 500 and 2000 p.s.i.g. with a catalyst comprised of between about .1 and 10% by weight of the oxides and sulfides of cobalt, between about 2 and 20% by weight of the oxides and sulfides of molybdenum, between about :1 and 5% by weight of ammonium fluoride, and the remainder essentially alumina at a space velocity of between about 0.5 and 20 liquid volumes of oil/hour/volume of catalyst, and recovering a lubricating oil having a viscosity index increased by at least 8 umts.

References Cited in the file of this patent UNITED STATES PATENTS 2,706,167 Harper et al. Apr. 12, 1955 2,734,019 Miller et a1. Feb. 7, 1956 2,760,907 Attane etal Aug. 28, 1956 2,787,582 Watkins et a1. Apr. .2, 1957 2,799,661 De Rosset July-16, 1957 2,800,429 Porter et a1. July 23, 1957 2,878,180 Watkins Mar. 17, 1959 OTHER REFERENCES cal Engineering Reviews), September 1957, part II (page "1526 only).

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent N00 3 1055.313 October 1, 1963 Louis Charles Gutberlet It is hereby certified that error appears in the above numbered patent reqiiring correction and that the said Letters Patent should read as corrected below.

Column 1 line 62, for "40%" read 10% column 4, line 17, for "oil having read oils which comprises contacting a lubricating oil having ""0 Signed and sealed this 7th day of April 1964..

(SEAL) Attest:

ERNEST we SWIDER EDWARD BRENNER Attesting Officer Commissioner of Patents 

1. A PROCESS FOR IMPROVING THE VISCOSITY INDEX OF LUBRICATING OIL HAVING A VISCOSITY INDEX IN THE RANGE OF -50 TO 100 WITH HYDROGEN AT A TEMPERATURE BETWEEN ABOUT 600* AND 900*F. AND A PRESSURE BETWEEN ABOUT 500 AND 3000 P.S.I.G. IN THE PRESENCE OF A CATALYST COMPRISED OF A MINOR AMOUNT OF THE OXIDES AND SULFIDES OF COBALT AND MOLYBDENUM, 0.1 TO 10% BY WEIGHT OF AN INORGANIC FLUORIDE, AND AN ALUMINA CARRIER, AND RECOVERING A LUBRICATING OIL HAVING AN INCREASED VISCOSITY INDEX. 